Method and device for reprofiling railway wheels

ABSTRACT

The present invention relates to a method for reprofiling wheel disks ( 7 ) or brake disks of a railway wheel or wheelset ( 6 ), rotatably mounted in bearing housings ( 9 ), by machining using a machine tool ( 12 ), which is designed to be portable, a wheel disk ( 7 ) of the railway wheel or the wheelset ( 6 ) being pressed against backup rolls ( 16 ) on its circumference by a clamping element ( 14, 15 ), which engages on at least one bearing housing ( 9 ), at least one of the backup rolls setting the railway wheel or the wheelset ( 6 ) into rotation, while simultaneously a tool ( 20 ) machines one of the wheel ( 7 ) or brake disks. The invention also relates to a machine tool ( 12 ) for carrying out the method. This machine tool ( 12 ) has a portable support frame ( 11 ) having a clamping element ( 14, 15 ) for engaging on a closed inner and/or outer bearing housing ( 9 ) of the railway wheel or wheelset ( 6 ), and at least one backup roll ( 16 ), which may be pressed against the outer circumference of the wheel disk ( 7 ), on whose bearing housing(s) ( 9 ) the clamping element ( 14, 15 ) engages, at a mutual distance to one another opposite to the clamping element ( 14, 15 ), a drive for at least one of the backup rolls ( 16 ), and a tool ( 20 ) for machining wheel ( 7 ) or brake disks ( 23 ) of the railway wheel or wheelset ( 6 ).

BACKGROUND OF THE INVENTION

The present invention relates to a method and a machine for machiningrailway wheels. The machining extends not only to the reprofiling ofwheels of individual wheel trucks, but also to the reprofiling of thewheels of wheelsets. It also extends to the reprofiling of brake disks,whether they are on individual wheel trucks or on the wheelsets of othertrucks. The requirement for carrying out the machining according to thepresent invention is that the affected railway wheel and/or the wheelsetis rotatably mounted in axle bearing housings. In this case, theindividual wheel and/or the wheelset to be machined may be in theuninstalled state, but the individual wheel and the wheelset may also bemachined in the installed state.

The wheels and brake disks of railway vehicles wear out due to materialwear, plastic deformation, and braking and acceleration processes. Forthese reasons, they have to be reprofiled from time to time, and this istypically performed through machining. For uninstalled wheelsets, thereprofiling is performed on surface lathes, which have a high metalremoving capacity. However, the outlay for dismounting and remountingthe wheelset is disadvantageous in this case, and this is particularlytrue for the wheelsets of traction vehicles, where it is required thatthe entire vehicle be operationally inspected after uninstallation of atraction wheelset.

For this-reason, the underfloor machine tools were developed, over whichthe railway vehicle, with the wheelsets installed, is pulled or travelsunder its own power. The underfloor machine tools are typically set upin a separate hall, below the level of the rails, in a pit. Since theyare designed for the machining of heavy vehicles using high metalremoving forces, they also have a correspondingly high weight. Inaddition, it is necessary that an underfloor machine tool be attached toa heavy foundation. The investments for facilities in which underfloormachine tools are operated are correspondingly large. In comparison tosurface machine tools, the metal removing performance of underfloormachine tools is somewhat lower.

For railway and local service companies which carry out their businessusing only a few vehicles, the investment for a wheelset machine tool,whether it is a surface or an underfloor machine tool, is hardly costeffective. These types of companies have therefore made the transitionto uninstalling the wheelsets to be machined and sending them tospecialized workshops, where the reprofiling of the wheel disks andmachining of the brake disks may be performed. However, even in the mainrailways, there are only a few workshops which are equipped withwheelset machine tools. The consequence of this is that uninstalledwheelsets or entire trains and/or cars must sometimes be transportedover long distances. In particular during times of more difficultoperation, in autumn or winter, for example, many wheelsets arise whichhave to be reprofiled in between times. In between times in this sensemeans that the wheelsets and/or wheels must be reworked between theactual inspection intervals determined by the company. The weatherconditions of autumn, with rain and falling leaves, lead to a peakdemand for wheelset machining in many rail traffic firms. Sometimes, thecapacity of the installed wheelset machine tools is not sufficient tocover the peak demand. Replacement times, non-availability, andtransportation and logistics costs are added to the actual machiningcost for the wheelsets.

SUMMARY OF THE INVENTION

From this, the object of the present invention results, of providing auniversal wheelset machine tool which may be used at different locationsas necessary. In this way, the transport of railway wheels, wheelsets,locomotives, trains, or cars is to be reduced and, simultaneously, themachine is to operate with sufficient precision for reprofiling of wheeldisks or machining of brake disks. The machine is to be provided withits own power supply devices, and it is also to be connectable toalready existing power supply devices of specialized workshops. Inparticular, the machine is to be used for machining both individual,uninstalled railway wheels and/or wheelsets and railway wheels orwheelsets which remain installed in the railway vehicle.

This object is achieved by a method for reprofiling wheel disks or brakedisks of a railway wheel or wheelset rotatably mounted in bearinghousings, through machining using a machine tool which

-   -   is designed to be portable,    -   a wheel disk of the railway wheel or the wheelset being pressed        against backup rolls on its circumference by a clamping element,        which engages on at least one bearing housing,    -   at least one of the backup rolls setting the railway wheel or        the wheelset into rotation, while simultaneously    -   a tool machines one of the wheel or brake disks of the railway        wheel or wheelset.

An essential idea of the present invention is that the device used forthe machining of the wheel or brake disks is portable, i.e., is mobile.The device is therefore no longer connected to a specific usagelocation, but may be brought to the respective railway vehicle to bemaintained and moved into the machining position.

For the machining of brake disks, both brake disks which are integratedinto the wheel disk of a railway wheel and those which are attached tothe shaft of a wheelset come into consideration. Typically, the outlineprofile of a wheel disk, using which the railway wheel or wheelset rollson the rail, is machined. This may be the outline profile of the samewheel disk of a wheelset which is simultaneously set into rotation.However, the outline profile of the wheel disk of a wheelset which liesopposite to the driven wheel disk may also be machined. Machining ofthis type on the opposite side of a wheelset may be advantageous ifadditional devices, e.g., generators, etc., are flange-mounted on theaxle bearing housing. While, for outline machining, both the runningsurface and the wheel flange or the outline of the running surface andwheel flange are machined, the reprofiling of brake disks is typicallyrestricted to surfacing these disks.

The machining may be performed by removing metal, whether throughlathing, milling, turn milling, or grinding. However, machining may alsobe provided in which the surface machined or to be machined is compactedwith the aid of a tool, as is known, for example, from press polishing.

In addition, it is provided that the railway wheel or the wheelset maybe subjected to an ultrasound test before or after the remachining. In asimilar way, the railway wheel or the wheelset is to be measured usingmeasurement technology before or after the reprofiling. The typicalmeasurement procedures are known to one of average skill in the art.

The present invention also relates to a machine tool for carrying outthe method. This machine tool is distinguished by a portable supportframe. It is equipped with a clamping element for engaging on a closedinner and/or outer bearing housing of a railway wheel or wheelset. Inaddition, at least two backup rolls are provided, which may be pressedagainst the outer circumference of the wheel disk, on whose bearinghousing(s) the clamping element engages, at a mutual distance to oneanother opposite to the clamping element, at least one of the backuprolls being provided with a drive. Furthermore, there is a tool formachining the wheel or brake disks of the railway wheel or wheelset inthe portable machine tool. A tool of this type is typically positionedon a support and carries out the machining at a location on thecircumference of the wheel disk where the backup rolls do not engage.

According to an advantageous exemplary embodiment, the frame of themachine tool is mounted on rollers or wheels and may be moved over thefloor. With the aid of the rollers or wheels, the wheelset machine toolmay be brought to any location of a workshop which offers the best spaceconditions. With the aid of the hoists typically present in a workshop,the railway wheel or the wheelset is lifted onto the wheelset machinetool and possibly fixed while the machining occurs. This is particularlytrue for railway wheels or wheelsets in the uninstalled state, sometimesa workshop hall not even having to be provided, but rather a suitableplace, covered or in the open, on the workshop grounds being able tosuffice.

The conditions are different for installed railway wheels or wheelsets.In the installed state, the railway wheel or the wheelset is permanentlyor removably connected to the associated railway vehicle. In railwayvehicles which travel on trucks, the wheelsets are permanently installedin the trucks. Even in the installed state, the reprofiling of therailway wheels or wheelsets may be carried out with the aid of themachine tool. For this purpose, the railway vehicle is placed on standsat lifting points provided particularly for this purpose. The height oflifting on the stands is between 1 and 2.5 m above the floor. In thisstate, the machine tool is pushed under the railway vehicle on standsand engaged with at least one of the railway wheels. The portablemachine tool may be introduced from the side of the railway vehicle onstands. However, it is typical to mount the portable machine tool onrollers or wheels which are guided along the workshop track. In thiscase, the machine tool is pushed in the longitudinal direction under therailway vehicle on stands until it is engaged with a wheelset.

During the machining of a railway wheel or wheelset, a torque acts onthe machine tool, which may be absorbed by attachment to the workshopfloor. For this purpose, it is advantageous to introduce additionalattachment means between the frame and the workshop floor. Forces due toaccelerations, in this case, particularly rotational accelerations ofvehicle motors located on the wheelset shaft, must also be absorbed bythe machine attachment. In this context, for example, a tool break maylead to sudden braking of the wheelset and briefly produce forces whichexceed the cutting forces of the metal-removing machining.

Normally, the weight of the machine tool on its mounting points on theworkshop floor is sufficient for absorbing the cutting forces. However,the machine tool may also be clamped onto the workshop track.

On the other hand, the machine tool is designed in such a way that anoffset of the machine by a few millimeters in relation to the wheelsetduring its machining is unimportant for the machining result. This istrue for an offset in the peripheral direction of the wheelset and inthe axial direction. The intrinsic stiffness of the machine tool is highenough to permit this type of offset.

In a further embodiment, the machine tool is attached to a vehicle. Thisvehicle may be a road vehicle or a railway vehicle. The machine tool isconveyed to the location of its use with the aid of such a vehicle. Inthis case, further devices may also be present on the vehicle, whichsupply the machine tool with the necessary power, whether it iselectrical power or power of a pressure medium, such as hydraulics orpneumatics. In addition, it is advantageous if the vehicle, using whichthe machine tool is transported, simultaneously also has hoists, usingwhich a railway wheel, a truck, or a wheelset may be lifted and/orlowered for machining on the machine tool. If the machine tool is notattached, a ramp may be provided, via which the machine tool may bemoved off of the transport vehicle, in order to be placed at thelocation at which the machining is to be performed. Even in such a case,the power supply device for the machine tool may also be carried by thetransport vehicle, however, it is also possible to connect the machinetool to already existing infrastructures for power supply of a workshop.

The clamping element, using which the bearing housing of the railwaywheel is grasped, may be operable both mechanically, via a spindle, andelectrically, pneumatically, or hydraulically. An electric motor or amotor which may have a pressure medium applied to it, whether it ishydraulic or pneumatic, may be provided for driving one or more of thebackup rolls. Lathing, broaching, milling, turn milling, grinding, ordeep rolling tools may be considered as machining tools. With the aid ofthese tools, both the outline of a wheel disk may be machined and theactive surfaces of a brake disk may be surfaced. In particular, eachbroaching, milling, turn milling, or grinding tool is to have its owndrive. Typically, the machining tools are positioned on supports andmachine the wheel disks on their circumference outside the backup and/ordrive rolls. For machining railway wheels in the installed state, havingthe clamping elements act vertically from top to bottom and positioningthe backup and/or drive rolls laterally outside the perpendicular wheelcenter suggests itself. The machining tool may then engage inperpendicular alignment below the clamping element. The measurement andtesting devices, in contrast, may be provided at any desired location ofthe circumference of the railway wheel to be tested, as permitted by thespace conditions. According to a further advantageous embodiment, anultrasound testing head is provided which applies ultrasound to thewheel disk of the railway wheel or a wheelset. A measurement head liesopposite to the testing head, which receives the ultrasound pulsespassing through.

It is also advantageous to measure the railway wheel and/or the wheeldisk to be machined before the machining and also after the machining.In this way, the success of machining is ensured. Mechanical caliperelements or optical triangulation calipers suggest themselves asmeasurement instruments.

Of course, high precision is sought with the reprofiling of railwaywheels and their brake disks according to the present invention. This isparticularly true for high-speed wheels. However, in vehicles which runat lower speeds, for example freight vehicles or secondary linevehicles, lower precisions may also be sufficient. In this case, thegoal of avoiding unnecessary wheelset transport or vehicle transfers isof primary concern. The machine tool is also equipped with guide platesor transport devices for chips, without these requiring a separatedescription. In the following, the present invention is described inmore detail with reference to two exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 each show, in a greatly simplified, schematicillustration, side views of two different wheelset machine tools.

DETAILED DESCRIPTION OF THE INVENTION

A railway vehicle 2 is on stands above workshop floor 1 in FIG. 1. Thevehicle is put on stands with the aid of perpendicular columns 3 whichstand laterally next to railway vehicle 2 on workshop floor 1. Railwayvehicle 2 itself rests on brackets 4, whose height may be adjustedvertically along columns 3. Bottom edge 5 of the car body of railwayvehicle 2 is at a height between 1 and 2.5 m above workshop floor 1.

FIG. 1 shows railway vehicle 2 viewed from its front end. A wheelset 6is connected to railway vehicle 2, which is intended for the purpose ofhaving both its wheel disks 7 run in a track. Wheel disks 7 areconnected to wheelset shaft 8 so that they rotate together and arerotatably mounted outside both wheel disks 7 in axle bearing housings 9.In the present example, wheelset 6 of a traction vehicle 2 is shown, onwhose wheelset shaft 8 a drive motor 10 is also positioned. Wheelset 6is connected to railway vehicle 2 via both bearing housings 9; thedetails of the connection are left out in FIG. 1 for reasons of bettervisibility.

Below railway vehicle 2 on stands, the frame 11 of a machine tool 12 isbrought into the operating position. Frame 11 is movable with the aid ofrollers 13 or wheels along a workshop track (not shown), via whichrailway vehicle 2 was previously rolled into the workshop. The width offrame 11 of machine tool 12 is dimensioned in such a way that it passesbetween columns 3 of the stands.

Clamping elements 14 project upward on both sides of frame 11. Theouter, upper ends of clamping elements 14 are provided with clampingclaws 15, using which they engage from above and outside on both closedbearing housings 9 of wheelset 6. Clamping elements 14 press wheelset 6downward until wheel disks 7 come into contact with backup rolls 16. Inthe present example, backup rolls 16 are positioned on an identicalshaft 17, which rests on an abutment 18, which is provided in frame 11of machine tool 12. Backup rolls 16 are rotatably mounted on shaft 17and at least one of both backup rolls 16 has its own drive (not shown),via which wheelset 6 is set into rotation upon contact of wheel disk 7and backup rolls 16.

In the present, simplified example, backup rolls 16 are illustrated asif they are located perpendicularly below wheel disks 7. However, theyare actually positioned below the perpendicular wheel center of wheeldisks 7, and laterally offset by an angle (not shown). In total, fourbackup rolls 16 of this type are provided in FIG. 1. Abutment 18 isdesigned in such a way that backup rolls 16 are elastically pressedlaterally from below against wheel disks 7. This elasticity is, forexample, achieved by implementing abutment 18 as a hydraulic orpneumatic cylinder which is assigned a pressure generator and a pressurestorage for the respective pressure means. Through the elastic support,backup rolls 16 may adjust themselves to possible eccentricities ofwheel disks 7, without slip occurring during driving.

At least one support 19, which is equipped with a tool 20, in thepresent case a cutting chisel, for example, is provided on frame 11.Instead of a single support 19, a further support (not shown), having acorresponding tool 20, may also be positioned on frame 11. Tool 20 isprovided for the purpose of machining the outline contour of wheel disks7. For this purpose, it is engaged on the circumference of a wheel disk7. Wheelset 7 is set into rotation via one of backup rolls 16, whiletool 20 performs the reprofiling of wheel disk 7 on the circumference ofwheel disk 7 by removing metal.

A further embodiment of a wheelset machine tool 12 is illustrated in theexemplary embodiment of FIG. 2. Wheelset machine tool 12 again has aframe 11, which is movable on rollers 21 over the floor on workshopfloor 1. Rollers 21 are not restricted to a track, so that machine tool12 of the exemplary embodiment of FIG. 2 may also be pushed laterally,next to columns 3, under railway vehicle 2 on stands.

Wheelset 6 is also connected to railway vehicle 2. A clamping element14, which engages from above, using a clamping claw 15, on bearinghousing 9 of wheelset 6, projects upward from frame 11. A backup roll 16rotatably mounted in a shaft 17 of frame 11 engages on the outercircumference of wheel disk 7, which is pressed against backup roll 16via bearing housing 9. As in the exemplary embodiment of FIG. 1, it istrue for backup rolls 16 in FIG. 2 that two backup rolls are provided ata lateral distance next to one another below the perpendicular center ofwheel disk 7.

A cutting chisel 20 is attached onto a support 19 so that it isadjustable in the radial direction on wheel disk 7. With the aid ofcutting chisel 20, the outline of wheel disk 7 of wheelset 6 is alsomachined in this case. In the case of the exemplary embodiment of FIG.2, only one single wheel disk 7 is machined at a time. After wheel disk7 is completely machined, machine tool 12 is pulled out from underrailway vehicle 2 laterally and, for example, on the right half of theillustration shown in FIG. 2, pushed back laterally under railwayvehicle 2 in the direction of arrow 22, in order to machine second wheeldisk 7. In addition to wheel disks 7, brake disks 23 are also attachedto wheelset shaft 8 so that they rotate together. Machine tool 12 isalso suitable for the purpose of surfacing lateral surfaces 24 of brakedisks 23.

In addition to the exemplary embodiment shown in FIGS. 1 and 2, amachine tool 12 according to the present invention may also be set up atany desired location outside or in a workshop hall. The machine tool setup in this way is then supplied an individual railway wheel or awheelset, so that the machining may be performed. After completion ofthe work, the machine tool is transported to another location, which maybe at a great distance to the location illustrated in the examples ofFIGS. 1 and 2. In the two simplified illustrations of FIGS. 1 and 2, allof the operating means known to one of average skill in the art are leftout for clarity, for example wheelset attachment, drive assemblies,power supply, power connections, and measurement and testing devices.

LIST OF REFERENCE NUMBERS

-   1 workshop floor-   2 railway vehicle-   3 columns-   4 brackets-   5 bottom edge-   6 wheelset-   7 wheel disk-   8 wheelset shaft-   9 bearing housing-   10 drive motor-   11 frame-   12 machine tool-   13 roller-   14 clamping element-   15 clamping claw-   16 backup roll-   17 shaft-   18 abutment-   19 support-   20 cutting chisel-   21 roller-   22 transport direction-   23 brake disk-   24 lateral surface

1. A machine tool for reprofiling wheel disks of a railway wheel orwheelset, rotatably mounted in bearing housings, comprising: a portablesupport frame, which is mounted on rollers which are movable on a track,having a clamping element for engaging on a closed inner and/or outerbearing housing of a railway wheel or wheelset, and at least one backuproll, for pressing against the outer circumference of a wheel disk, onwhose bearing housing(s) a clamping element engages, at a mutualdistance to one another opposite to the clamping element a drive for atleast one of the backup rolls, and a tool for machining wheel or brakedisks of the railway wheel or wheelset.